3v swap troubleshoot

SteveIH

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I had an issues like that with my 07 and the issues ended up being fuel pump. It would say lean sometimes and shutter tried injectors and tunes and I thought it couldn't be fuel pump then it quit all together replaced pump and have never had issues since.
 

Joe combs

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Check the hoses from the intake hose to the valve covers... I also agree with the comment about checking your O2 wiring since you are rich on one side and lean on the other. Also check to make sure you dont have an exhaust leak around the exhaust manifold to cat pipe. The right side O2 is in the cat pipe, the drivers side in in the manifold... if you have a way for air to be pulled in at the leak it could create the lean code you describe.
 

Mustang Mark

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Very good chance you have your O2 sensor wires mixed up driver to passenger and vise versa with having one side rich and one lean... ask me how I know...
 

RavenGT

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I just swapped a new 3v into my 05. The old one didn't have any major modifications and it just has a Borla exhaust, Bama tuner, and cold air. You're basic stuff to get you the 200 extra hp you want.

200 HP from mufflers and a tune? No. Not even remotely close.
 

greyGT

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I just swapped a new 3v into my 05. The old one didn't have any major modifications and it just has a Borla exhaust, Bama tuner, and cold air. You're basic stuff to get you the 200 extra hp you want... Anyway, I got the swap done and everything seems to be in order. The engine is running lean though and when the tune is put back in stock, it starts and dies. In a 93 octane tune, it runs and drives but it stutters like it's lean. I checked the engine light and it does confirm that it's lean. This light isn't on all the time even when it stutters. Everything like the injectors seems to be working properly, they did operate perfectly before the swap, and I changed my gaskets out. My experience on anything newer than a foxbody is extremely limited and I'm looking for any ideas.

I’d check the signal wire colors on both upstream O2 sensors. It is possible to mismatch the upstream and downstream connectors. Passenger side upstream O2 sensor, 1 of the 4 wires should be grey with a light blue stripe (GY-LB). Driver side, 1 of the 4 wires should be red with a black stripe (RD-BK). If you see RD-LG and VT-LG, fronts and rears are reversed. If there is a track nearby, try taking it for a WOT run. If you hammer it and it doesn't go lean, you probably don't have a fueling problem. If you leave traction control on, and you spin, it will cut fuel. Disable traction control at your own risk.
 
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MrBhp

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Argh, I hate unhappy endings. I feel so unfulfilled.
 

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